The present invention relates to a LED (light-emitting diode) lighting device comprising at least a first and a second LED powered by a switched mode power supply.
Such a device is disclosed e.g. in EP 0716485 A1.
In such a device, a switched mode power supply (SMPS) is controlled to supply a constant current to one or more LEDs. The LED light output may then be controlled through pulse width modulation by varying the duty cycle of a bypass switch which is connected in parallel with the LED/LEDs.
The SMPS is superior to a linear power supply in terms of energy efficiency. However, the precision of the supplied current may not be sufficient for all applications, because the load varies, which induces transients in the used current feedback system.